Rotary compressor



' Oct. 14, 1941.!y P. o. DE RATE Em 2,259,021

ROTARY COMPRESSOR Inma/wim 72 l Pezlz dezarwz'ef Dudzeysmbble,

Patented Oct. 14, 1941 ROTARY COMPRESSOR Pedro 'rtiz de Zarate and Dudley Steward n Drabble, Buenos Aires, Argentina Application January Z7, 1940, Serial No. 315,994

In Great Britain May 3, 1939 2 Claims.

This invention relates to improvements in rotary compressors and lan essential object ofV the same is to provide an apparatus of this kind with certain improvements of constrnction whereby the use and the working of the same will be` A further object of our invention is to providev an impeller structure which during compression will provide a resilient gas packing between adjacent impeller yand casing surfaces to additionally seal the Icompression process.

this invention are especially adapted for use yin connection with rotary blowers or compressors, consisting of two rotary impellers of B-shaped cross section, preferably of hollow construction, mounted on parallel shafts and operated by a synchronized motion in opposite directions, so that generating lines lying in the peripheral surface of each of said impellers parallel to its axis will move nearly in contact with generating lines of the adjacent impeller and the inner surface of the corresponding casing.

The improvement according to this invention substantially consists in providing the above mentioned rotary impellers with longitudinal slots, in free communication with the inner chambers of the same, so as to allow of the fluid circulating freely between the outer part and also the inner part of each of said impellers. By means of this arrangement, the difliculties caused by any possible expansion of the impellers in the radial direction owing to the same becoming heated during the compression of the gases, will be avoided together with possible resultant frictional engagement oi the impeller with the casing wall, since the slot permits the impeller tip to expand tangentially instead of radially. Said slots are preferably arranged along the generating lines lying in the surface which are farthest from the axis of rotation of each impeller, viz., those which move in contact with the inner surface of the compressor casing, whereby during compression the gases which press outwardly from the inner chambers of said impellers .through the aforesaid slots, against the inner The improvements which form the object of surface of the casing will operate in the manner of a resilient packing and thus increase the tightness of seal` and, accordingly, the eiective yield of the apparatus.

A further improvement vinaccordance with this invention consists lin that within the admission andlthe outlet ports of the compressor casing, suitably perforated partitions yarearranged, the inner surfaces of which form a continuaton of the inner generating lines lying in the inner peripheral force of said casing, parallel -toV its axis whereby the ow in the suction chamber as well as thecompression chamber will be controlledand the working of the apparatus will be facilitated to a corresponding degree, due to decreased turbulence.

Another improvement characterizing this invention consists in providing the casing of the apparatus with external detachable caps', formed on their inner surface with grooves or recesses within which correspondingly shaped projections fit, which are provided on the opposite rim of said casing,r so as to form a socket joint which, while'allowing of readily mounting and dismounting said caps in their correct position, will assure atight seal.

The invention also has in view-other objects whichwill more fully be referred to in the following description. Y

In order that our invention maybe clearly understood and readily carried into practice, a preferred embodiment of the same has been shown by way of example in the accompanying drawings, in which:

Figure 1 illustrates a vertical cross section of an improved type of compressor, in accordance with this invention.

Figure 2 is a longitudinal sectional elevation of said compressor, taken on the line A--A of Figure 1.

Figure 3 is a fragmentary plan view of the same device, partially sectional, so as to show some of the inner parts of the device, and

Figure 4 shows a detail of said compressor, as viewed from one of its front sides.

The same reference characters have been used to indicate like or corresponding parts in all the views.

In the form of construction shown, I indicates the outer casing of a rotary compressor of the kind above described, the rotary impellers 2 of which are mounted on two parallel shafts 3 and 4, conveniently supported by detachable outer caps 5 ln ball bearings 6 or the like, provided therein, Rotary motion is transmitted t0 Said,

impellers 2 from a suitable type of engine by a pulley or similar driving means which rotates the shaft 4, geared to the shaft 3 by means of gear wheels I and 8, respectively. Said gear Wheels being of equal diameter, will cause the impellers 2 to rotate synchronized in opposite directions, as indicated by the arrows in Figure 1. The casing I, in turn, is provided at its entrance with a chamber 9 to which is connected the feed pipe I for the gas or fluid to be compressed, while at its other end, a similar chamber Il is formed, connected to the outlet duct I2 which leads the compressed fluid to the internal combustion engine or other place of use, the said chambers extending substantially over the entire length of the casing I. The inner surface of casing I corresponds substantially to the surface generated by the line lying in the peripheral surface of the impeller at its tip, parallel to the impeller axis and farthest therefrom.

The rotary impellers 2, in accordance with this invention, are entirely hollow, being formedwith independent inner chambers I3, closed at their ends and communicating with the space outside the same by means of one or several slots I4, extending preferably'over the entire length of said chambers, so as to allow of the fluid freely circulating between-the interior of said impellers and the space outside the same, for the purpose of reducing the effects caused by thermal metallic expansion. As has already been stated before, said slots I4 are preferably arranged along the generating lines Which lie in the peripheral surface of the impeller at its tip which are substantially in contact with the casing I, whereby the conditions of tightness or seal between the casing and the impellers are considerably increased and the useful yield of the'cornpressor is accordingly improved.

With reference to Figures 1 to 3, it will be noted that near the admission and the outlet ends of the casing I, suitable partitions I5 and I6 have been arranged, the inner sides of which form aV continuation of the internal surface of said casing, so as to increase the interval of con-v tact between this latter and the outermost generating lines lying in the peripheral surface of the impellers 2 at their tips; said partitions I5 and I 6, which have for object to control the flow in the suction and compression chambers for the iiuid, are formed with a suitable number of bores I'I and I8, of appropriate dimensions, conveniently distributed over a part or over the entire surface of said partitions.

By referring to Figure 2, it will also be seen that the leasing I is closed at both end by means of detachable caps 5, provided with suitable means for forming a tight seal. the free edges of the casing project beyond the paddles 2 and their protruding parts are lodged, in the manner of a socket joint, in the grooves or recesses I9, formed on the inner surface of the caps, said grooves being of a profile adapted to the transverse shape of the casing I. By means of this arrangement, a perfectly tight seal is secured while permitting of said caps 5 being readily fixed in their adjusted position, or detached from the casing, when required.

Owing to its excellent features of construction and operation, as well as to its high working yield, the improved compressor as above described, is particularly adapted for being used to a considerable advantage for the compression of gaseous or liquid fluids in general, but more particularly for supplying motors of automobiles and similarV internal combustion engines.

Having now clearly described and ascertained the `nature of our said invention and in what manner the same is to be performed, we declare that what we claim and desire to secure by Letters Patent, is:

1. In a rotary compressor, a pair of impellers mounted with parallel axes, a casing surrounding saidvimpellers, means for synchronously driving said impellers, said impellers having respective peripheral contours that during rotation mutually substantially engage each other and substantially engage the inner surface of said casing, said impellers being rhollow and being provided with longitudinal slots parallel to their axes which extend the full axial length of said impellers and through the respective peripheral shells of said impellers providing a communicating channel between the hollow interior thereof and said casing.

2. A compressor according to claim l, the longitudinal slots of said impellers being formed on the outermost tip ends thereof which are nearest to the inner surface of said casing.

PEDRO ORTZ DE ZARATE. DUDLEY STEWARD DRABBLE.

To this end, 

